1. Field of the Invention
The invention relates to a blood pump, and more particularly, the invention relates to a centrifugal blood pump system with a turbine drive assembly.
2. Brief Description of the Related Art
Blood pumps used in surgical procedures such as cardiopulmonary bypass (CPB) and coronary artery bypass grafting (CABG) are single-use devices. These blood pumps are generally powered by a reusable electric motor which drives the pump through a magnetic coupling. However, the reusable electric motors are not sterilizable. Thus, the motor and attached pump are positioned outside the sterile surgical field at a location away from the patient. The disposable pump is connected to the patient by long lengths of tubing which transport the patient's blood to and from the blood pump. The long lengths of tubing increase the priming volume of the pump which is the amount of the patient's blood and/or saline which must be drawn into the tubing and the pump to prime the pump before blood begins to be returned to the patient.
Long lengths of tubing connecting the pump to the patient also increase the amount of foreign material which comes into contact with the patient's blood, increasing trauma to the patient. A typical CPB circuit includes several feet of flexible tubing that the patient's blood flows through. In order to prevent blood clots, the patient's blood is generally treated with Heparin. The use of Heparin is preferably minimized because Heparin prevents the blood from clotting.
In either stopped heart or beating heart surgery, it is desirable to minimize the priming volume of the blood pump by placing the pump as close as possible to the surgical site. By placing the pump closer to the surgical field, the amount of saline required to prime the bypass circuit is reduced which reduces the likelihood that a transfusion will be required. Previous attempts to move the blood pump closer to the patient have involved the use of a cable drive for the blood pump which allows the sterile pump to be located within the sterile surgical field while being driven from a remotely located motor. However, the cable used in the cable drive system may break causing pump failure.
Accordingly, it would be desirable to provide a blood pump system which allows the blood pump to be positioned within the surgical field close to the surgical site to minimize the priming volume of the pump. In addition, it would be desirable to drive a blood pump in a manner which does not generate heat as in a system using an electric motor.